North American Numbers Source-cited · ownership disclosed
Area code
671
In service
United States · since 1997

Guam

Area code 671 is the sole area code for the U.S. territory of Guam. It replaced Guam's ITU country code when the island joined the NANP in 1997.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Guam
Type
geographic
Status
in service
In service since
1997
Projected exhaust
2142 Q4

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 671 is

The entire island of Guam..

Communities served wholly or partly by 671:

HagåtñaDededoTamuningYigoBarrigadaMangilao
B · Relationships

How it relates to other codes

The codes 671 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

What's changing. No overlay. Single territory-wide code.
C · History

How 671 got here

1997-07-01
Created with the start of permissive dialing, replacing Guam's former ITU country code as it joined the NANP.
Source: Wikipedia
2021-10-24
Transitioned to 10-digit dialing due to the 988 designation.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
128
Prefixes available
672

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 671 with another code →
Sources
Wikipedia ↗
Area code 671
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.